O-Ringing Possibilities

[wedgehead]

Well guys I took the Barracuda to the track on Sunday. I used the NOS on it for the first time. It's a 200 hp kit. Well I blew a head gasket at #6 cyl. When I had the motor done it was not o-ringed. It currently has #1008 Fel Pro. I was told by the engine builder that they would hold up so I took him at his word. My question to you guys is how much difference is it in O-ringing the heads and O-ringing the block? I have heard of guys o-ringing the heads to be able to use them on different blocks without having it done each time. It would also be much simpler to take the heads to the machine shop for O-ringing than to tear down the entire engine for o-ringing. Do you think the seal will be just as effective? I should have listened to 9sec340!! But down here everybody has the bottle and if you don't you'll wish you did. Mid 10's doesn't just don't cut it here either. Thank you guys in advance, Wedgehead

[rumblefish360]

Wheres done here?

O ringing the heads let the head go from block to block. For sealing, it can't be beat.
10sec340 was right.
It shouldn't be hard to correct.

[sanborn]

Let me make a suggestion.

Did you retorque the heads after initial startup? It should be done.

Are you using studs ?

I have never had real good success with 1008 gaskets with iron heads, 8553 Fel Pros worked better for me because they don't have the stainless ring. But, being a poor old oval racer(and a dirty one at that) we don't use nitrous.

The reasons head gaskets blow is block/cylinder head flex due to torque. And the middle cylinders always seem to give the trouble.

[dirty dan]

Hey Wedge head
I don`t know the perticulars of your engine.
But I would not spend a nickel on getting my heads o-ringed.
Here are a few of the resons why in no particular order.
One is the need for sonic testing to find out if your particular castting is thick enough around the chambers.
Remember just because they have the same castting # doesn`t make them the same thickness.
Also O-ringing the heads will cost more then o-ringing the block becuase it is more dificult an operation.
Now haveing pointed this out let me give you the real resons.
1the heads are subject to warpage. Should this happen you would have to resurface the heads.Thus the end of your o-ring job.
This will leave you with 2 choices. One is to regrove the head if it`s thick enough.
Or surface it enough to eliminate the groove and go back to a regular gasket. Either way how many times do you want to do this to a set of heads that you have real $$ in.
Another reson is that it may cause crackes in the combustion chambers down the road. This is never a good thing.
It wouldn`t take long to trash a set like that.
I can understand the temptation to travle that path.
but it is really a dead end.

I know you didn`t ask but here is some more NOS info.
When selecting a size to be used.
A large CID engine will take more NOS then a small one.
That is assumeing they are both stock engines.
As an example( Strictly from what I have seen.)
A stock compresstion ratio 340 will stand up to 175 shot of Nos
on fellpro blue gaskets.And a 440 will take up to 235 on the same type gasket.((NOT RECOMENDED on cast pistions))
If You use this as a giud it may save you some greif.
With higher compresstion ratios the #`s will drop.
Hope it helps.

[Doug Wilson]

d.d. is right. I spent a lot of time on the phone talking to smart people about o-ringing, and every one of these smart people said to o-ring the block, unless I was going to use throw away heads.

[6Cuda6]

I would take a few seconds and call around to some of the local engine builder that do NOS motors as it sound to me like you got way to much cylinder pressure for your motor on that shot, just remember that you'll always find the weakest link, if your engine builder said the motor would be fine and you lost the head gasket i'd be worried about loosing something else once it was sealed up properly..

[gotcha]

Here's a little more info for ya. The oval track engines that we ran for years always had head gasket problems. It is very important that the head surface and the block surface be perfectly straight. We eventually O-ringed the blocks per Mopar engineers. Unless the heads are considered throwaways...do the block.

The real problem is the lack of headbolts. (10) on the smallblock.

Nitrous and smallblocks do not get along well. Cylinder pressures are high....and sealing is marginal without the nitrous. I know ten people will write and say they run 150-200 shot of nitrous all the time....make a hundred passes a night, etc., etc., etc. all on the smallblock with stock head gaskets. I just don't see it happening in the real world. You tried.

O-ring the block, heads and block perfectly straight, use studs, the correct gasket for the application, and run only a wet system with plenty of fuel. Lean conditions and nitrous can do a lot of damage. "technicolor hood removal".

On the other hand....big blocks love nitrous, have lots of headbolts, and very strong deep-skirted blocks.